Prognostic value of computed tomography derived fractional flow reserve for predicting cardiac events and mortality in kidney transplant candidates

BackgroundCardiac screening using coronary computed tomography angiography (CCTA) in kidney transplant candidates before transplantation yields both diagnostic and prognostic information. Whether CT-derived fractional flow reserve (FFRCT) analysis provides prognostic information is unknown.This study aimed to assess the prognostic value of FFR_CT for predicting major adverse cardiac events (MACE) and all-cause mortality in kidney transplant candidates.MethodsAmong 553 consecutive kidney transplant candidates, 340 CCTA scans (61%) were evaluated with FFR_CT analysis. Patients were categorized into groups based on lowest distal FFR_CT; normal >0.80, intermediate 0.80–0.76, and low ≤0.75. In patients with ≥50% stenosis, a lesion-specific FFR_CT was defined as; normal >0.80 and abnormal ≤0.80.The primary endpoint was MACE (cardiac death, resuscitated cardiac arrest, myocardial infarction or revascularization). The secondary endpoint was all-cause mortality.ResultsMedian follow-up was 3.3 years 2.0–5.1]. MACE occurred in 28 patients (8.2%), 29 patients (8.5%) died.When adjusting for risk factors and transplantation during follow-up, MACE occurred more frequently in patients with distal FFR_CT ≤0.75 compared to patients with distal FFR_CT >0.80: Hazard Ratio (HR): 3.8 (95%CI: 1.5–9.7), p ?< ?0.01.In the lesion-specific analysis with <50% stenosis as reference, patients with lesion-specific FFR_CT >0.80 had a HR for MACE of 1.5 (95%CI: 0.4–4.8), p ?= ?0.55 while patients with lesion-specific FFR_CT ≤0.80 had a HR of 6.0 (95%CI: 2.5–14.4), p ?< ?0.01.Abnormal FFR_CT values were not associated with increased mortality.ConclusionIn kidney transplant candidates, abnormal FFR_CT values were associated with increased MACE but not mortality. Use of FFR_CT may improve cardiac evaluation prior to transplantation.